I think that is the root of the confusion here. Ill try to brek it down quick and easy. First off, yup. + to - to + to - is series. In series, the cells will have additive voltage, that is 1.5 V + 1.5 V = 3V. Thats cool BUT, to max current will be the max current of ONE cell. So if the Li Ion Cells are 1.5 V with 2 amps max, with 2 cells in series we get 3V at 2 amps.
Parallel is + to + and - to - .
in parallel current is cumlitive wich means 2 of the above cells gives you 4 A,,,,, BUT voltage is = to V max of one cell. So we get 1.5 V and 4 Amps max.
So you can take your 8 cells and put them in series and get the 8V or so but still only get 2 Amps from the pack.
Put the same 8 cells in parallel and get 16 Amps but only 1.5 V . The 1.5 V may not even be enough to spin the fan.
The best solutioin for this low current cell, is a series / parallel combination pack. That means we make up say two packs of 4 cells in series, and put the two pack in parallel with each other and get a total of 6 V @ 4 Amps.
You can get 6 V @ 6 Amps by adding another 4 cells in series with each other by in parallel with the other 2 sets of 4. Thats not a bad voltage and current figure, but you now are up to 12 cells!
. Like was said before in the post, if you can get it to fly, it will be up there a while as moto calc has suggested.
So you can see how even though you can get either the Voltage or the Amps you need but not both. You need to double or tripple the cell count to get the numbers you need.
You can get the numbers you need from the correct series / parallel combo, BUT, you now need to do the weight, space, and cost figures and see if it adds up.
Now, realize that as you start to push the Max current of a cell, the Voltage begins to drop and the cell can be damaged
. Also, the nominal voltage of a cell differs by the material it is made from and nominal voltage is the voltage the cell maintains with NO LOAD. There is ALWAYS a drop in voltage when a cell is loaded.
Hope this helps, sorry about any misspelled stuff, I am a BAD speller
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[This message has been edited by JasonJ (edited 08-01-2001).]